Vinmajorines C – E,Monoterpenoid Indole Alkaloids from Vinca major

Three new monoterpenoid indole alkaloids, vinmajorines C–E ( 1 – 3 ), along with 18 known analogues ( 4 – 21 ), were isolated from the whole plants of Vinca major. The new structures were elucidated as (5α,15β,16R,17α,19β,20α,21β)‐10,17‐dimethoxy‐21‐methyl‐18‐oxa‐5,16‐cycloyohimban‐19‐ol ( 1 ), (5α,15β,16R,17α,20α,21β)‐10‐methoxy‐21‐methyl‐18‐oxa‐5,16‐cycloyohimban‐17‐ol ( 2 ), and (5α,15β,16R,17α,20α,21β)‐10‐methoxy‐21‐methyl‐18‐oxa‐5,16‐cycloyohimban‐17‐yl acetate ( 3 ), respectively, by extensive NMR and MS analysis and comparison with known compounds. Compounds 1 – 3 were evaluated for their cytotoxic activities against five human cancer cell lines, compounds 1 and 3 showing moderate cytotoxic activities.     

Nucleotides. Part LXXVI

A series of new fluorescing 8‐(6‐hydroxyhexyl)isoalloxazine (=8‐(6‐hydroxyhexyl)benzo[g]pteridine‐2,4(1H,3H)‐dione) derivatives 4 – 13 were synthesized from 6‐[(6‐hydroxyhexyl)amino]uracil ( 2 ) with 1‐chloro‐4‐nitrosobenzene via 8‐chloro‐10‐(6‐hydroxyhexyl)isoalloxazine ( 3 ) and subsequent substitution of the Cl‐atom of 3 by various amines (Scheme). Analogously, 8‐substituted 10‐{3‐[(2,2‐dimethyl‐1,3‐dioxolan‐4‐yl)methoxy]propyl}isoalloxazines 19, 20 , and 23 – 25 were prepared which yielded on deprotection the corresponding 10‐[3‐(2,3‐dihydroxypropoxy)propyl]alloxazines 21, 22 , and 26 – 28 . Their conversion into the 3″‐O‐(4,4′‐dimethoxytrityl) derivatives 29 – 33 and subsequent transformation into the corresponding 2″‐(2‐cyanoethyl N,N‐diisopropylphosphoramidites) 34 – 38 led to new building blocks for oligonucleotide synthesis. A series of 21‐mer oligodeoxyribonucleotides carrying the fluorescing isoalloxazine 37 in various positions of the chain were assembled in a DNA synthesizer. Combination with the complementary sequence yielded the stable duplexes 40 – 54 showing by the melting temperatures T_m that the fluorophor ( F ) does not harm the stability of the unmodified duplex 39 (Table).     

Synthesis of Monosaccharide‐Derived Spirocyclic Cyclopropylamines and Their Evaluation as Glycosidase Inhibitors

The glucose‐, mannose‐, and galactose‐derived spirocyclic cyclopropylammonium chlorides 1a – 1d, 2a – 2d and 3a – 3d were prepared as potential glycosidase inhibitors. Cyclopropanation of the diazirine 5 with ethyl acrylate led in 71% yield to a 4 : 5 : 1 : 20 mixture of the ethyl cyclopropanecarboxylates 7a – 7d , while the Cu‐catalysed cycloaddition of ethyl diazoacetate to the exo‐glycal 6 afforded 7a – 7d (6 : 2 : 5 : 3) in 93–98% yield (Scheme 1). Saponification, Curtius degradation, and subsequent addition of BnOH or t‐BuOH led in 60–80% overall yield to the Z‐ or Boc‐carbamates 11a – 11d and 12a – 12d , respectively. Hydrogenolysis of 11a – 11d afforded 1a – 1d , while 12a – 12d was debenzylated to 13a – 13d prior to acidic cleavage of the N‐Boc group. The manno‐ and galacto‐isomers 2a – 2d and 3a – 3d , respectively, were similarly obtained in comparable yields (Schemes 2 and 4). Also prepared were the differentially protected manno‐configured esters 24a – 24d ; they are intermediates for the synthesis of analogous N‐acetylglucosamine‐derived cyclopropanes (Scheme 3). The cyclopropylammonium chlorides 1a – 1d, 2a – 2d and 3a – 3d are very weak inhibitors of several glycosidases (Tables 1 and 2). Traces of Pd compounds, however, generated upon catalytic debenzylation, proved to be strong inhibitors. PdCl is, indeed, a reversible, micromolar inhibitor for the β‐glucosidases from C. saccharolyticum and sweet almonds (non‐competitive), the β‐galactosidases from bovine liver and from E. coli (both non‐competitive), the α‐galactosidase from Aspergillus niger (competitive), and an irreversible inhibitor of the α‐glucosidase from yeast and the α‐galactosidase from coffee beans. The cyclopropylamines derived from 1a – 1d or 3a – 3d significantly enhance the inhibition of the β‐glucosidase from C. saccharolyticum by PdCl , lowering the K_i value from 40 μM (PdCl ) to 0.5 μM for a 1 : 1 mixture of PdCl and 1d . A similar effect is shown by cyclopropylamine, but not by several other amines.     

Synthesis and Bioactivity of New Chalcone Derivatives as Potential Tyrosinase Activator Based on the Click Chemistry

A new series of (E)‐1‐(4‐((1‐benzyl‐1H‐1,2,3‐triazol‐4‐yl)methoxy)phenyl)‐3‐phenylprop‐2‐en‐1‐one 1a (4‐((1‐benzyl‐1H‐1,2,3‐triazol‐4‐yl) methoxy)phenyl)‐1‐phenylprop‐2‐en‐1‐one 1b – 15b were designed, synthesized based on click chemistry, and biologically evaluated for their activity on tyrosinase. The result showed that most of prepared compounds 1a – 15a have potent activating effect on tyrosinase, especially for 3a , 8a – 10a and 14a – 15a . Among them, compounds 10a and 14a demonstrated the best activity with EC₅₀=1.71 and 5.60 µmol·L^?1 respectively, even better than the positive control 8‐MOP (EC₅₀=14.8 µmol·L^?1). Conversely, compounds 3b , 5b – 6b , 9b – 10b , and 15b induced enzymatic inhibition on tyrosinase.     

ent‐Kaurane Diterpenes and Further Constituents from Wedelia trilobata

Two new ent‐kaurane diterpenes, wedelidins A ( 8 ) and B ( 9 ), together with eighteen other constituents, including the sesquiterpenoids 1 and 2 , ent‐kaurane diterpenes 3 – 7 , triterpenoids 10 and 11 , steroids 12 – 14 , and flavonoids 15 – 17 as well as benzene derivatives 18 – 20 , were isolated from the aerial parts of Wedelia trilobata. The structures of wedelidins A ( 8 ) and B ( 9 ) were elucidated by extensive spectroscopic analyses (including UV, IR, NMR, and MS). Furthermore, the structures of compounds 2 and 3 were confirmed by X‐ray single‐crystal diffraction analyses.     

A Hydroxylated Lupeol‐Based Triterpenoid Ester Isolated from the Scurrula parasitica Parasitic on Nerium indicum

(3β,7β)‐7‐Hydroxylup‐20(29)‐en‐3‐yl hexadecanoate ( 1 ), a new lupeol‐based triterpenoid ester, along with sixteen known compounds, 7β,15α‐dihydroxylup‐20(29)‐ene‐3β‐O‐palmitate ( 2 ), lupeol palmitate ( 3 ), lupeol ( 4 ), 3‐oxolup‐20(29)‐ene ( 5 ), ursolic acid ( 6 ), cycloeucalenol ( 7 ), stigmasterol ( 8 ), β‐sitosterol ( 9 ), β‐daucosterol ( 10 ), quercetin ( 11 ), quercetin 3‐O‐α‐L ‐arabinoside ( 12 ), quercetin 3‐O‐α‐L ‐rhamnoside ( 13 ), catechin ( 14 ), gitoxigenin 3‐O‐α‐L ‐rhamnoside ( 15 ), gitoxigenin 3‐O‐α‐D ‐glucoside ( 16 ), and digitoxigenin 3‐O‐α‐L ‐rhamnoside ( 17 ), was isolated from the leaves of the Southern China mistletoe, Scurrula parasitica Linn parasitic on Nerium indicum Mill . Their structures were elucidated by spectroscopic analyses, including 2D‐NMR techniques. Cytotoxic activities of compounds 1 – 7 and 11 – 17 were evaluated against three cancer cell lines, PANC‐1, HL‐60, and SGC‐7901, revealing that compounds 4, 6, 11 , and 15 – 17 exhibited effective cytotoxicities, while others were inactive. A structure? activity relationship study of compounds 1 – 5 indicated that the 3‐OH group in lupeol‐based triterpenoids is essential for antitumor activity.     

Cytotoxicities and Topoisomerase I Inhibitory Activities of 2‐[2‐(2‐Alkynylphenyl)ethynyl]benzonitriles, 1‐Aryldec‐3‐ene‐1,5‐diynes,and Related Bis(enediynyl)arene Compounds

The activities of a series of acyclic enediynes, 2‐(6‐substituted hex‐3‐ene‐1,5‐diynyl)benzonitriles ( 1 – 5 ) and their derivatives 7 – 23 were evaluated against several solid tumor cell lines and topoisomerase I. Compounds 1 – 5 show selective cytotoxicity with Hepa cells, and 2‐[6‐phenylhex‐3‐ene‐1,5‐diynyl]benzonitrile ( 5 ) reveals the most‐potent activity. Analogues 8 – 10 and 13 – 22 also have the same effect with DLD cells; 1‐[(Z)‐dec‐3‐ene‐1,5‐diynyl)‐4‐nitrobenzene 21 shows the highest activity among them. Moreover, 1‐[(Z)‐dec‐3‐ene‐1,5‐diynyl]‐2‐(trifluoromethyl)benzene ( 20 ) exhibits the strongest inhibitory activity with the Hela cell line. Derivatives 9, 10, 18 , and 23 display inhibitory activities with topoisomerase I at 87 μM . The cell‐cycle analysis of compound 5 , which induces a significant blockage in S phase, indicates that these novel enediynes probably undergo other biological pathways leading to the cytotoxicity, except the inhibitory activity toward topoisomerase I.     

Tumor‐Promoting Diterpene Esters from Latex of Euphorbia cauducifolia L.

Tumor‐promoting characteristics of seven esters, 1 – 7 , obtained from the latex of Euphorbia cauducifolia L. was appraised by carrying out NMRI mice back skin. The structures of 1 – 7 were elucidated by spectroscopic techniques like ¹H‐ and ¹³C‐NMR, 2D‐NMR (HMQC, HMBC, HOHAHA (homonuclear Hartmann–Hahn), NOESY, and NOE), FT‐IR, UV, and MS as esters of 17‐hydroxyingenol, namely 17‐[(2Z,4E,6Z)‐deca‐2,4,6‐trienoyloxy]ingenol ( 1 ), 3‐O‐angeloyl‐17‐[(2Z,4E,6Z)‐deca‐2,4,6‐trienoyloxy]ingenol ( 2 ), 3‐O‐acetyl‐20‐O‐angeloyl‐17‐hydroxyingenol ( 3 ), 17‐(acetyloxy)‐3‐O‐angelyl‐ingenol ( 4 ), 20‐O‐acetyl‐3‐O‐angeloyl‐17‐hydroxyingenol ( 5 ), 3‐O‐angelyl‐17‐(benzoyloxy)ingenol ( 6 ) and 20‐O‐acetyl‐3‐O‐angelyl‐17‐(benzoyloxy)ingenol ( 7 ). Compounds 1 – 4 were isolated for the first time, whereas 5 – 7 are known metabolites but detected for the first time in this plant. Biological investigations revealed that these compounds are tumor promoters.     

Hydroacridines: Part 23. 1H and 13C NMR spectra of sym‐octahydroacridine,its 9‐(3‐pyridyl) and 9‐(4‐pyridyl) derivatives and the corresponding N(10)‐oxides. An experimental approach to the diamagnetic anisotropy of the pyridine nucleus

The complete ¹H NMR chemical shift assignments of 1,2,3,4,5,6,7,8‐octahydroacridine ( 1 ), 1,2,3,4,5,6,7,8‐octahydro‐9‐(3‐pyridyl)acridine ( 2 ), 1,2,3,4,5,6,7,8‐octahydro‐9‐(4‐pyridyl)acridine ( 3 ) and the corresponding N(10)‐oxides 1a , 2a and 3a , respectively, were achieved on the basis of 400 MHz ¹H NMR spectra and proton–proton decoupling, HMQC and NOEDIFF experiments. The spectral data for the above compounds provided the first experimental evidence of the difference in the anisotropy effect of the two non‐symmetrical moieties of the pyridine nucleus, and allowed us to ascertain that the shielding effect of the moiety defined by the C(2′)—N—C(6′) atoms is weaker than that of the C(3′)—C(4′)—C(5′) moiety. The ¹³C NMR spectra of 1 – 3 and 1a – 3a and the effect of N(10)‐oxidation on the ¹³C NMR chemical shifts are also discussed. The N‐oxidation of 2 and 3 with m‐chloroperbenzoic acid occurred regiospecifically, affording the N(10)‐oxides 2a and 3a free of N(1′)‐oxide isomers. Copyright © 2002 John Wiley & Sons, Ltd.     

Synthesis of Some New 2‐Oxo‐N‐[(10H‐phenothiazin‐10‐yl)alkyl] Derivatives of Azetidine‐1‐carboxamides

The synthesis of a new series of 4‐aryl‐3‐chloro‐2‐oxo‐N‐[3‐(10H‐phenothiazin‐10‐yl)propyl]azetidine‐1‐carboxamides, 4a – 4m , is described. Phenothiazine on reaction with Cl(CH₂)₃Br at room temperature gave 10‐(3‐chloropropyl)‐10H‐phenothiazine ( 1 ), and the latter reacted with urea to yield 1‐[3‐(10H‐phenothiazin‐10‐yl)propyl]urea ( 2 ). Further reaction of 2 with several substituted aromatic aldehydes led to N‐(arylmethylidene)‐N′‐[3‐(phenothiazin‐10‐yl)propyl]ureas 3a – 3m , which, on treatment with ClCH₂COCl in the presence of Et₃N, furnished the desired racemic trans‐2‐oxoazetidin‐1‐carboxamide derivatives 4a – 4m . The structures of all new compounds were confirmed by IR, and ¹H‐ and ¹³C‐NMR spectroscopy, FAB mass spectrometry, and chemical methods.     

Cytotoxic Withaphysalins from Physalis minima

A novel withanolide, withaphysalin P ( 1 ) with a nine‐membered ring, and six other new withaphysalins, 2 – 7 , together with the three known withaphysalins 8 – 10 were isolated from Physalis minima L. The structures were deduced by means of spectroscopic analyses, and that of withaphysalin P ( 1 ) was confirmed by a single‐crystal X‐ray diffraction analysis. Plausible biosynthetic pathways were postulated (Scheme 1). All compounds were tested for their antiproliferative activities toward the human colorectal‐carcinoma HCT‐116 cells and human nonsmall‐cell lung‐cancer NCI‐H460 cells (Table 4). Compounds 1 – 3, 7 – 10, 7a , and 7b displayed moderate cytotoxic activity against the two human cancer cell lines.     

Regioselective 1,3‐Dipolar Cycloadditions of (1Z)‐1‐(Arylmethylidene)‐5,5‐dimethyl‐3‐oxopyrazolidin‐1‐ium‐2‐ide Azomethine Imines to Acetylenic Dipolarophiles

The 5,5‐dimethylpyrazolidin‐3‐one ( 4 ), prepared from ethyl 3‐methylbut‐2‐enoate ( 3 ) and hydrazine hydrate, was treated with various substituted benzaldehydes 5a – i to give the corresponding (1Z)‐1‐(arylmethylidene)‐5,5‐dimethyl‐3‐oxopyrazolidin‐1‐ium‐2‐ide azomethine imines 6a – i . The 1,3‐dipolar cycloaddition reactions of azomethine imines 6a – h with dimethyl acetylenedicarboxylate (=dimethyl but‐2‐ynedioate; 7 ) afforded the corresponding dimethyl pyrazolo[1,2‐a]pyrazoledicarboxylates 8a – h , while by cycloaddition of 6 with methyl propiolate (=methyl prop‐2‐ynoate; 9 ), regioisomeric methyl pyrazolo[1,2‐a]pyrazolemonocarboxylates 10 and 11 were obtained. The regioselectivity of cycloadditions of azomethine imines 6a – i with methyl propiolate ( 9 ) was influenced by the substituents on the aryl residue. Thus, azomethine imines 6a – e derived from benzaldehydes 5a – e with a single substituent or without a substituent at the ortho‐positions in the aryl residue, led to mixtures of regioisomers 10a – e and 11a – e . Azomethine imines 6f – i derived from 2,6‐disubstituted benzaldehydes 5f – i gave single regioisomers 10f – i .     

Transformation of Amino Acids into Nonracemic 1‐(Heteroaryl)ethanamines by the Enamino Ketone Methodology

N‐Protected L ‐phenylalanines 1a,b were transformed, via the corresponding Weinreb amides 2 and ethynyl ketones 3 , into chiral enamino ketones 4 (Scheme 1). Similarly, L ‐threonine 6 was transformed in four steps into the enamino ketone 10 . Cyclocondensations of 4 and 10 with pyrazolamines 11 , benzenecarboximidamide ( 12 ), and hydrazine derivatives 18 afforded N‐protected 1‐heteroaryl‐2‐phenylethanamines 15a – e, 16, 17 , and 21a – k and 1‐heteroaryl‐1‐aminopropan‐2‐ols 23a,b in good yields (Schemes 2 and 3). Finally, deprotection by catalytic hydrogenation furnished free amines 22a – g and 24a,b (Scheme 3).     

A Novel Synthesis of 4‐Pyridazineacetic Acids via Ring Expansion of N‐Cyanomethylated 3‐Pyrazoline‐4‐acetic Acids

A novel synthetic route to 4‐pyridazineacetic acids 10 – 12 has been achieved by the ring‐expansion reaction of N‐cyanomethylated 3‐pyrazoline‐4‐acetic acids 7 – 9 . 1H‐Pyrazole‐4‐acetic acids 1 – 3 were reacted with iodoacetonitrile in the presence of triethylamine in refluxing acetonitrile to give the corresponding C‐cyanomethylated 1H‐pyrazole‐4‐acetic acids 4 – 6 as major products together with N‐cyanomethylated 3‐pyrazoline‐4‐acetic acids 7 and 8 as minor products. On the other hand, reactions of 1 and 3 with chloroacetonitrile in the presence of triethylamine in refluxing chloroform afforded the corresponding N‐cyanomethylated 3‐pyrazoline‐4‐acetic acids 7 and 9 as major products. Thermal treatment of 7 – 9 with sodium hydride in N,N‐dimethylformamide caused ring expansion to yield the corresponding 4‐pyridazineacetic acids 10 – 12 .     

Investigation of the Interactions of β‐Peptides with DNA Duplexes by Circular Dichroism Spectroscopy

The interaction of β‐peptides with the DNA duplexes of dA₂₀dT₂₀ and a GCN4‐binding CRE sequence was examined. To gauge the factors that govern these interactions, two β‐pentadecapeptides, 1 and 2 , a β‐dodecapeptide, 3 , three β‐decapeptides, 4 – 6 , three β‐heptapeptides, 7 – 9 , and β‐octaarginine 10 were designed and synthesized. The β‐peptides were conceived to adopt a β‐peptide 3₁₄ helix, in which the side chains at position i and i + 3 are aligned vertically along one side of the helix. The side chains of Lys, Asn, and Arg were positioned such that potential H‐bonding sites were created for a helical conformation to interact with the base pairs of DNA. CD Analysis showed that β‐peptides 1, 2 , and 10 interacted with dA₂₀dT₂₀. In addition, β‐peptides 1 and 2 showed significant interaction with a DNA‐duplex 20mer containing the ATF/CREB recognition sequence for the regulatory protein GCN4. It is impossible, at this stage of the investigation, to make a safe proposal about the actual nature of the interaction of the structures(s) of the complexes, the formation of which is suggested by the CD spectra reported herein.     

Kinetics of Hydride Abstractions from 2‐Arylbenzimidazolines

The rates of the hydride abstractions from the 2‐aryl‐1,3‐dimethyl‐benzimidazolines 1a – f by the benzhydrylium tetrafluoroborates 3a – e were determined photometrically by the stopped‐flow method in acetonitrile at 20 °C. The reactions follow second‐order kinetics, and the corresponding rate constants k₂ obey the linear free energy relationship log k₂(20 °C)= s(N+E), from which the nucleophile‐specific parameters N and s of the 2‐arylbenzimidazolines 1a – c have been derived. With nucleophilicity parameters N around 10, they are among the most reactive neutral C? H hydride donors which have so far been parameterized. The poor correlation between the rates of the hydride transfer reactions and the corresponding hydricities (ΔH⁰) indicates variable intrinsic barriers.     

Synthesis and Cytotoxicity Evaluation of Metal‐Chelator‐Bearing Flavone,Carbazole, Dibenzofuran,Xanthone, and Anthraquinone

2‐(Aryloxymethyl)‐5‐benzyloxy‐1‐methyl‐1H‐pyridin‐4‐ones 8a – 8g , 2‐(aryloxymethyl)‐5‐hydroxy‐4H‐pyran‐4‐ones 9a – 9g , and 2‐(aryloxymethyl)‐5‐hydroxy‐1‐methyl‐1H‐pyridin‐4‐ones 10a – 10g were prepared from the known 5‐benzyloxy‐2‐(hydroxymethyl)pyran‐4‐one ( 3 ) in a good overall yield. These compounds were evaluated in vitro against a three‐cell lines panel consisting of MCF7 (breast), NCI‐H460 (lung), and SF‐268 (CNS), and the active compounds passed on for evaluation in the full panel of 60 human tumor cell lines derived from nine cancer cell types. The results indicated that 5‐hydroxy derivatives are more favorable than their corresponding 5‐benzyloxy precursors ( 10a – 10g vs. 8a – 8g ), and 1‐methyl‐1H‐pyridin‐4‐ones are more favorable than their corresponding pyran‐4(1H)‐ones ( 10a – 10g vs. 9a – 9g ). Among these three types of compounds, 2‐(aryloxymethyl)‐5‐hydroxy‐1‐methyl‐1H‐pyridin‐4‐ones 10a – 10g were the most cytotoxic; they inhibited the growth of almost all the cancer cells tested. On the contrary, compound 8a (a mean GI₅₀=27.8 μM ), 8b (38.5), 8d (11.0), and 8e (30.5) are especially active against the growth of SK‐MEL‐5 (a melanoma cancer cell) with a GI₅₀ of <0.01, 5.65, 0.55, and 0.03 μM , respectively (cf. Table 2).     

Synthesis and Microbial Studies of New Pyridine Derivatives-Ill

2-Amino substituted benzothiazole 4a--4I and p-acetamidobenzenesulfonyl chloride 2 were used to prepare 2-（p-aminophenylsulfonamido） substituted benzothiazole 6a--6I using mixture of pyridine and acetic anhydride which formed an electrophilic complex （N-acetyl pyridinium） to facilitate condensation to give desired product by removal of HC1. 2-{p-[（3-Carboxypyrid-2-y1）amino]phenylsulfonamido}benzothiazoles 8a--81 were synthesized from 2-chloropyridine-3-carboxylic acid 7 and 6a--6I in 2-ethoxy ethanol using Cu-powder and K2CO3. Acid chlorides 9a--91 were condensed with 2-hydroxyethyl piperazine 10 and 2,3-dichloropiperazine 11 for amide deriva- tives 2-（p-（（3-（4-（2-hydroxyethy1）piperazin-1-ylcarbonyl）pyrid-2-y1）amino）phenylsulfonamido）benzothiazoes 12a -121 and 2-{p-[3-（2,3-dichloropiperazin-l-ylcarbonyl）pyrid-2-ylamino]phenylsulfonamido}benzothiazoles 13a- 131 respectively. The structures of the new compounds have been established on the basis of their chemical analysis and spectral data （IR, 1↑H NMR and mass）. All the compounds have been screened for their antibacterial and antifungal activities.     

Inclusion Complexes of Coenzyme Q10 with Polyamine‐Modified β‐Cyclodextrins: Characterization,Solubilization, and Inclusion Mode

The inclusion‐complexation behavior of coenzyme Q10 (CoQ10) with the three polyamine‐modified β‐cyclodextrins (CDs) 1 – 3 was investigated in both solution and the solid state by means of NMR, XRD, and FT‐IR spectroscopy. The results showed that the apparent solubility of CoQ10 increased linearly upon addition of hosts 1 – 3 , giving A_L‐type phase‐solubility curves. These hosts 1 – 3 were able to solubilize CoQ10 to high levels, up to 1.35, 1.52, and 1.44 mg/ml (calculated as CoQ10), respectively. The host 2 with a moderate‐length chain is the most suitable for inclusion complexation of CoQ10. Accroding to the ROESY experiments, the MeO groups of CoQ10 and the tether of 2 can be co‐included into the cavity of β‐CD through the induced‐fit interaction between host and guest. The binding ability of modified β‐CDs 1 – 3 upon complexation with CoQ10 are discussed from the viewpoints of the size/shape‐matching relationship and the induced‐fit concept between host CDs and guest CoQ10 molecule.     

Four New Nor‐Diterpenoid Alkaloids from Aconitum brachypodum

Four new C₁₉‐nor‐diterpenoid alkaloids, named brachyaconitines A–D ( 1 – 4 ), were isolated from the roots of Aconitum brachypodum Diels. Their structures were elucidated as 3‐O‐acetyl‐20‐deethyl‐20‐formylaconitine ( 1 ), 3‐O‐acetyl‐19,20‐didehydro‐20‐deethylaconitine ( 2 ), 3‐O‐acetyl‐8‐de(acetyloxy)‐7,8,17,20‐tetradehydro‐20‐deethyl‐7,17‐secoaconitine ( 3 ), and 1‐O‐methylflavaconitine ( 4 ) by means of MS, IR, 1D‐ and 2D‐NMR analyses. The structure of compound 1 was confirmed by an X‐ray diffraction experiment.